The moorings consist of top chain, riser wire, ground chain, adjustment / dip zone chain and excursion limiter chain , ground wire, anchor chain and Anchors.
As-Left Data
The pre laid moorings shall be installed and each line shall be fully tensioned at the anchor. The pre laid moorings shall be installed up to the adjustment chain, and the ground chain, riser wire and top chain will be connected prior to the buoy hook-up.
Anchor Position and Orientation
Coordinates for the anchor shall be taken using USBL fixes on top of the fluke. The anchor heading can be measured by ROV Gyro. Sometimes anchors get dragged during tensioning and while repositining coordinates are different compared to design location. Flukes are better locations to get the coordinates compared to Shackle as sometimes aftet final tensioning shackels get buried inside of mud.
Anchor Penetration Status after Final Tensioning
Following the final tensioning of the system detailed information on penetration of the anchor can be accessed by recording various depth by ROV.
Mooring Line Lay Routes
The mooring line lay routes shall be surveyed by ROV prior to the installation of the system . All lines shall be laid within design corridors.
Comparison to Design Data and Proposed chain Cut Lengths
Detailed information of the differences in range between the design and final positions of anchor and socket in ground chain shall be computed. For assessing the amount of adjustment chain to be cut, range calculations using the LBL array between the upper socket and buoy centre position should be taken.Based on the calculated cut lengths the number of links to be removed from the adjustment chain shall be calculated and presented in Table . The cut removal of each link reduces the length of the chain by the difference of link length and twice of link diameter.
Line Twist Information
Following the installation of the pre-laid moorings a ROV survey shall be performed on each line to determine if any twists were present that require rectification. Based on information from the wire manufacturer a maximum allowable rotation shall be determined over full range of wire.If observed twist or rotation on any line is greater than the allowable, the vessel shall carry out remedial work immeditely or during the top chain installation to remove these turns.
As-Left Data
The pre laid moorings shall be installed and each line shall be fully tensioned at the anchor. The pre laid moorings shall be installed up to the adjustment chain, and the ground chain, riser wire and top chain will be connected prior to the buoy hook-up.
Anchor Position and Orientation
Coordinates for the anchor shall be taken using USBL fixes on top of the fluke. The anchor heading can be measured by ROV Gyro. Sometimes anchors get dragged during tensioning and while repositining coordinates are different compared to design location. Flukes are better locations to get the coordinates compared to Shackle as sometimes aftet final tensioning shackels get buried inside of mud.
Anchor Penetration Status after Final Tensioning
Following the final tensioning of the system detailed information on penetration of the anchor can be accessed by recording various depth by ROV.
Mooring Line Lay Routes
The mooring line lay routes shall be surveyed by ROV prior to the installation of the system . All lines shall be laid within design corridors.
Comparison to Design Data and Proposed chain Cut Lengths
Detailed information of the differences in range between the design and final positions of anchor and socket in ground chain shall be computed. For assessing the amount of adjustment chain to be cut, range calculations using the LBL array between the upper socket and buoy centre position should be taken.Based on the calculated cut lengths the number of links to be removed from the adjustment chain shall be calculated and presented in Table . The cut removal of each link reduces the length of the chain by the difference of link length and twice of link diameter.
Line Twist Information
Following the installation of the pre-laid moorings a ROV survey shall be performed on each line to determine if any twists were present that require rectification. Based on information from the wire manufacturer a maximum allowable rotation shall be determined over full range of wire.If observed twist or rotation on any line is greater than the allowable, the vessel shall carry out remedial work immeditely or during the top chain installation to remove these turns.
